/*
 * Copyright 2012 Netflix, Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

package com.netflix.logging.log4jAdapter;

import java.util.Arrays;
import java.util.List;

import org.apache.log4j.helpers.FormattingInfo;
import org.apache.log4j.helpers.PatternConverter;
import org.apache.log4j.helpers.PatternParser;
import org.apache.log4j.spi.LocationInfo;
import org.apache.log4j.spi.LoggingEvent;

import com.netflix.blitz4j.LoggingContext;


/**
 * A custom parser class that provides a better performing implementation than the one in log4j for finding location information such
 * as class, line number etc.
 *
 * @author Karthik Ranganathan
 */
public class NFPatternParser extends PatternParser {
    private static List<Character> contextCharList = Arrays.asList(Character.valueOf('c'),
            Character.valueOf('l'),
            Character.valueOf('M'),
            Character.valueOf('C'),
            Character.valueOf('L'),
            Character.valueOf('F'));

    public NFPatternParser(String pattern) {
        super(pattern);

    }

    protected void finalizeConverter(char c) {
        if (contextCharList.contains(Character.valueOf(c))) {
            PatternConverter pc = new NFPatternConverter(formattingInfo, c);
            addConverter(pc);
            currentLiteral.setLength(0);
        } else {
            super.finalizeConverter(c);
        }
    }

    private static class NFPatternConverter extends PatternConverter {
        private char type;

        NFPatternConverter(FormattingInfo formattingInfo, char type) {
            super(formattingInfo);
            this.type = type;
        }

        @Override
        public String convert(LoggingEvent event) {
            LoggingContext.getInstance().shouldGenerateLocationInfo(event.getLogger());
            LocationInfo locationInfo = LoggingContext.getInstance().getLocationInfo(event);
            if (locationInfo == null) {
                return "";
            }
            switch (type) {
                case 'M':
                    return locationInfo.getMethodName();
                case 'c':
                    return event.getLoggerName();
                case 'C':
                    return locationInfo.getClassName();
                case 'L':
                    return locationInfo.getLineNumber();
                case 'l':
                    return (locationInfo.getFileName() + ":"
                            + locationInfo.getClassName() + " "
                            + locationInfo.getLineNumber() + " " + locationInfo
                            .getMethodName());
                case 'F':
                    return locationInfo.getFileName();
            }
            return "";

        }


    }
}